HG or XDR: which freehub does your bike need?

Close-up of a rear hub and freehub body with the spokes running away from it

Shimano 11- and 12-speed drivetrains take the HG freehub. SRAM 12-speed road drivetrains take XDR. That covers almost every disc road bike sold in the last few years — but "almost" is doing some work in that sentence, so here is how to check rather than assume.

Look at the cassette, not the bike

The freehub is the splined body the cassette slides onto. What decides it is the cassette you are running, not the frame, not the groupset badge on the crank.

Three checks, no tools:

  1. Read the smallest sprocket. If the smallest cog has 10 teeth, it is XDR. An HG body physically cannot take a 10-tooth sprocket — the standard is built around an 11-tooth minimum. This one check settles most bikes.
  2. Read what is printed on the cassette. Shimano cassettes are marked CS-R8100, CS-R9200, CS-HG800 and so on; all of those are HG. SRAM road cassettes marked XG-1270, XG-1290 or similar are XDR.
  3. Look at the end of the freehub body. XDR is visibly longer and narrower, with fine splines running its whole length and a threaded lockring at the far end. HG is shorter with a distinct step near the outboard end.

The cases that trip people up

A SRAM badge on the crank does not settle it. What the wheel needs is decided by the cassette, and a bike can leave a shop with parts from more than one place. Count the teeth on the smallest sprocket rather than reading the groupset.

XD is not XDR. XD is the mountain bike version and is about 1.8 mm shorter. They look nearly identical and they are not interchangeable. If your bike is a road or gravel bike with SRAM road gearing, you want XDR.

Campagnolo needs its own body. Campagnolo and Campagnolo-compatible Ekar cassettes fit neither of these. If that is your drivetrain, talk to us before ordering.

11-speed on a 12-speed wheel is usually fine. An HG body built for 12-speed takes an 11-speed cassette with a spacer, which is a normal and supported arrangement.

If you order the wrong one

It is not the end of the world. A freehub body is a serviceable part and can be changed. But it is a part you would be paying for twice, and a wheel you would be waiting on twice, so a minute of checking now is worth it — and if you are unsure after reading the above, ask us instead of guessing.

Choose the freehub on the product page before you add to cart. Every wheelset on this site offers both, at the same price.

What else is fixed, and what is not

The freehub is the only fitment choice you make. Everything else is the same across the range: 12 mm thru axles, 12 × 100 mm front and 12 × 142 mm rear, Center Lock rotor mounts, and a rim 24 mm internal and 31.5 mm external.

That axle standard is what almost every disc road bike built since around 2018 uses. There is no rim-brake version and no quick-release version.

Not sure?

Send us the bike — make, model and year — and we will tell you which freehub it takes. That is a faster conversation than a return, and we would rather have it before you order. English or French, whichever you prefer.

The rest of what people ask before buying is answered on the questions page.

Once fitment is settled

The freehub is the only compatibility question. What is left is preference: which rim depth to take, and whether a rider weight limit narrows the field for you.

Back to blog

Still asked

I run 11-speed Shimano. Which freehub do I order?

HG. An HG body made for 12-speed takes an 11-speed cassette with a spacer, which is a normal and supported arrangement, so you are not buying anything you will have to change if you upgrade later.

Can I change the freehub later?

Yes — a freehub body is a serviceable part, not something moulded into the hub. But it is a part you would be paying for twice and a wheel you would be waiting on twice, so it is worth a minute of checking before you order. If you are unsure, send us the bike and we will tell you.

Is there a freehub on the front wheel too?

No. A freehub is the ratcheting body the cassette sits on, and only the rear wheel has one. The front hub simply spins. When you choose HG or XDR you are choosing for the rear wheel; the front is the same either way.

Does the freehub decide how many gears I can run?

Indirectly. The body sets which cassettes physically fit, and the cassette sets the gears. XDR exists because SRAM wanted a 10-tooth smallest sprocket, which an HG body cannot take. Within each standard there are 11- and 12-speed cassettes, so the freehub narrows your options rather than fixing your gear count.